The pulp and paper industry is the greatest co nsumer of biomass fuels and feedstock; as a result it generates biomass waste, which represents a great amount of heat energy available. Besides the waste generated in the industry, th e paper and pulp production chain involves an important forestry activity, in which generally the wood is taken and the biomass residues are abandoned at the forest, that represents between 15 and 25% of the tree dry mass. This research focuses on the solid residues generated at the forest (leaves, barks, thin branches and thick branches) as well as the residues of the pulp and paper industry (fines, barks, chips and organic sludge), characterizing them as fuel. The objective is also estimate the electricity generation potential by the combustion of biomass residues through the steam Rankine cycle. The characterization is based on a range of analysis, studying the thermal degradation (thermal analysis - TG and DSC), and determining the heating value, the elemental, immediate and structural composition. Also, th e ash elemental composition is established. The material used is taken from a hybrid of Eucalyptus urophylla x Eucalyptus grandis. The studied biomass is suitable to be used as fuel in industrial boilers. The forest residues, which have some disadvantages regarding to others biomass like wood, improved its characteristics as it remains at the forest for a period of time , decreasing its moisture and reducing the ash, chlorine and potassium contents. The sludge combustion could be energy deficient due to its high moisture content and its low heating value. The electricity generation potential is high, since the productivity of waste is large and its he ating value is similar to the original wood. We conclude that without considering the logistics issues, the biomass waste has great energy potential, generally untapped.